Although there were varieties of prior arts regarding windmills, apparently no means had ever achieved the objects of enabling any blade or vane to identify the alternation of lee wind and head wind to perform instant swinging to appropriate positions to sail up to 250 degrees and streamline against windward resistance no more than 110 every circle of rotation, and none of the prior arts ever provided any easily recoverable and removable means for maintenance and anti-typhoon purposes, any anti-friction rotary speed multiplying transmission and regulating means for the "low-rotary-speed featured" vertical-axle windmill, and any means to overcome the loss of centripetal and centrifugal component wind forces from the blade to the vertical axle at a time.
Although a U.S. Pat. No. 4,818,180 relating to the vertical-axle windmill ever innovated and owned by the inventor of the present invention did enable the blade therein to sail about 260 degrees a circle and to convert centripetal and centrifugal component forces to a same torque direction, its swinging and counterbalancing means were less satisfactory and need further improvement.